Fuses according to this invention are generally used as semiconductor fuses and, therefore, have low i.sup.2.t values and low i.sub.p let-through currents. However, fuses embodying this invention are not limited to the above purpose of protecting semiconductor devices.
It appears that the ancestor of fuses of the kind under consideration are disclosed in U.S. Pat. No. 2,713,098 to K. W. Swain, July 12, 1955 for CURRENT-LIMITING FUSIBLE PROTECTIVE DEVICES. These composite fuses performed quite satisfactorily, but the terminal members used for connecting the fuses into the electric circuit to be fused were quite expensive to manufacture.
A simple but less desirable solution consisted in affixing rectangular terminal members to the end surface of the ferrules of the fuses. Solder joints were arranged at the interfaces between the terminal members and the end surfaces of the ferrules of the fuses to minimize the electrical resistance between these two parts. These solder joints have a tendency to melt at currents at which the fuse or fuses do not yet blow.
In another kind of prior art fuses the aforementioned solder joints were replaced by large masses of solder, inserted between the ferrules of the fuses and the terminal members. These heat sinks prevent the fusion of the solder at overloads at which the fuse or fuses do not blow, however, require large masses of solder which greatly increase the weight and the price of the fuses.
It is the principal object of this invention to provide improved fuses not subject to the above drawbacks and limitations of prior art fuses. A more specific object of this invention is to provide fuses whose voltage drop is small in the absence of any solder or similar joint. Other objects and advantages of this invention will become apparent as this specification proceeds.